Animation.CrossFade
CrossFade(animation: string, fadeLength: float = 0.3F, mode: PlayMode = PlayMode.StopSameLayer): void;
void CrossFade(string animation, float fadeLength = 0.3F, PlayMode mode = PlayMode.StopSameLayer);
def CrossFade(animation as string, fadeLength as float = 0.3F, mode as PlayMode = PlayMode.StopSameLayer) as void
Description

Fades the animation with name animation in over a period of time seconds and fades other animations out.

If mode is PlayMode.StopSameLayer, animations in the same layer as animation will be faded out while animation is faded in. if mode is PlayMode.StopAll, all animations will be faded out while animation is faded in.

If the animation is not set to be looping it will be stopped and rewinded after playing.
	// Fade the walk cycle in and fade all other animations in the same layer out.
	// Complete the fade within 0.2 seconds.
	animation.CrossFade("Walk", 0.2);
using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    void Example() {
        animation.CrossFade("Walk", 0.2F);
    }
}
import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	def Example() as void:
		animation.CrossFade('Walk', 0.2F)

Another example:
	// Makes a character contains a Run and Idle animation 
	// fade between them when the player wants to move
	function Update () {
		if (Mathf.Abs(Input.GetAxis("Vertical")) > 0.1)
			animation.CrossFade("Run");
		else
			animation.CrossFade("Idle");
	}
using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    void Update() {
        if (Mathf.Abs(Input.GetAxis("Vertical")) > 0.1F)
            animation.CrossFade("Run");
        else
            animation.CrossFade("Idle");
    }
}
import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	def Update() as void:
		if Mathf.Abs(Input.GetAxis('Vertical')) > 0.1F:
			animation.CrossFade('Run')
		else:
			animation.CrossFade('Idle')